Wooden skyscrapers

You know, I can’t help feeling that thee’s a risk here:

British Columbia is no stranger to wooden giants. Along its western coast, Douglas fir and Sitka spruce trees topping 60 meters in height have in some cases weathered nearly a millennium of storms.

Now a growing chorus of architects, foresters and engineers want the province’s biggest city to grow another cluster of wooden giants: timber skyscrapers.

Already, Vancouver’s 18-storey Brock Commons tower stands as a testament to the vast possibilities of wood. Once the world’s tallest timber building, it was built cheaper, faster and with less environmental impact than a comparable steel and concrete structure would have been – offsetting an estimated 2,432 metric tonnes of carbon.

Now the provincial government has changed its building codes, effectively doubling the height limit for wood-frame buildings to 12 storeys (Brock Commons was granted an exception when it was built). The Canadian government is expected to match BC’s codes nationwide.

Hmm, well. As Grenfell showed, building in concrete doesn’t make a place fireproof. But still:

Despite popular misconceptions of wood as fire-prone and unstable, it can be a robust and innovative building material.

That doesn’t quite answer the misconception, does it?

15 thoughts on “Wooden skyscrapers”

  1. We’re not talking about wood, as in growing on trees, we’re talking about cross laminated timber (CLT), which is a sort of three dimensional plywood. The original wood is shredded into fibre strips and rebuilt into a solid, with fibres running in all directions for isotropic strength, using modern superglues. If you’ve ever seen marine plywood you’ll know how tough that is, and CLT is even tougher. Hit it with enough heat and it will char, but it won’t burn until long after everything else has gone up in flames. It’s actually a bloody good structural material even if the greens do like it.

  2. Norra Dame (to use the American pronunciation): is public knowledge about the fire any further forward?

  3. The Japanese build in wood because when it collapses in an earthquake it’s quck and cheap to replace it.

  4. The US developer Hines is making a big push into wooden buildings in North America and Australia, so I presume the economics are sound. From their blurb it seems to be a marketing-led exercise; they clearly see customers for this.

    Not sure what the exact cost/speed of construction implications are, but for example they promote the natural wood interior as part of the attraction, thus saving them the cost of finishing the interior.

  5. ‘… with less environmental impact than a comparable…’

    If you don’t count deforestation, felling, transportation, energy used in the saw-mills and processing plants, and adhesives, or CO2 emissions from the entire forest to building process and waste wood disposal/incineration.

    Of course that would be ‘good’ and ‘sustainable CO2.

    I wonder why we stopped using wood and started using steel and concrete?

  6. Building regs here allow two stories in timber frame for housing. If you want to build higher you can put your two storey home on a steel or concrete structure. My home is 3 storey steel frame. The Tohoku earthquake left some stress marks where the wallpaper connects the skin to the frame. I’m very happy with steel thank you very much.

  7. They like wood in BC, there’s usually enough wood on the outside of the building and inside that using it in the frame isn’t going to add much to the fire risk, and as stated already not all wood is equally combustible even naturally let alone processed/treated stuff.
    I usually have a mixed load of soft and hard wood for the fireplace at winter and there’s a notable difference between the two.

  8. Wood frames are one of the reasons that homes in California survive earthquakes so we’ll. It tends to flex and disappate the quake energy instead of breaking and collapsing. The new glue-lam products compare well with steel on strength, cost, and weight. Consider the small damage from the recent Ridgecrest earthquake with a similar sized earthquake elsewhere in the world. Vancouver has a similar earthquake environment.

  9. I go to Salt Lake City quite a bit. Honestly, it’s weird seeing the height of the buildings they are putting up out of wood. But nothing this big yet.

  10. Laminated wood has significant advantages over steel in a fire. At relatively modest temperatures a steel structure weakens and collapses (see WTC as an example) whereas laminated wood retains its strength far longer and chars but doesn’t normally burn well until temperatures are extreme.

    One one stage (and may still be) it was in NZ mandated for the beams of structures like school halls – specifically because it was considered considerably safer than steel though not actually any cheaper.

    It isn’t a wonder material, it does take some preparing and it does have an environmental impact (though it can be made from specifically grown timber not just old-growth), but it is certainly worth considering in many circumstances.

    Just because the “Greens” like it doesn’t automatically make it a bad idea, though it does more often than not.

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